Suggest Treatment For Itchy Rashes On Scalp, Shoulder Blade And Wrist

I have a rash that started in my scalp. I have been battling it since late November. It has now spread to my shoulder blades, arms around the wrists, and around My torso. IT ITCHES tremendously. I can calm it with a steroid cream for a short while. I have also tried a prednisone pack. Since coming off the medication the rash has spread twice as fast. I can wipe it with rubbing alcohol and get some relief. The rash look like a heat rash. It does not get watery or oozy like poison ivy. Any suggestion would be appreciated - especially for the scalp.